With Bay Area population forecast to increase to 8 or 9 million people, the region is grappling with where current and future residents will live and work. In San Francisco population density is rising in the trendy South of Market and Mission Bay areas, where housing is close to social media and other jobs. Commercial and residential real estate is thriving, including many new green buildings. But most of the region's 6 million residents don't live or work in an urban core. Infill and suburban development will both be needed to accommodate more people. The fact that buildings account for approximately 40 percent of greenhouse gas emissions means future growth will have to be more efficient and smarter to meet state mandated goals for reducing carbon pollution. Are taller skyscrapers part of the answer? Can office parks really be green? A conversation about building the future of the Bay Area.

China's urbanization is creating new cities at a mind-boggling rate. Gleaming office towers are rising all over the country and massive amounts of land are being converted to residential and commercial uses. Is China growing in an energy- and carbon-smart fashion? What will be the hallmarks of these new metropolitan centers? How will they shape 21st century trends in architecture, land use and urban living?